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<h3><a name="SECTION0016336000000000000000"></a><a name="optparse-standard-option-types"></a>
<br>
14.3.3.6 Standard option types
</h3>

<p>
<tt class="module">optparse</tt> has six built-in option types: <code>string</code>, <code>int</code>, <code>long</code>,
<code>choice</code>, <code>float</code> and <code>complex</code>.  If you need to add new option
types, see section&nbsp;<a href="optparse-extending-optparse.html#optparse-extending-optparse">14.3.5</a>, Extending <tt class="module">optparse</tt>.

<p>
Arguments to string options are not checked or converted in any way: the
text on the command line is stored in the destination (or passed to the
callback) as-is.

<p>
Integer arguments (type <code>int</code> or <code>long</code>) are parsed as follows:
<blockquote>
</blockquote>
<ul>
<li> 
if the number starts with <code>0x</code>, it is parsed as a hexadecimal number

<p>
</li>
<li> 
if the number starts with <code>0</code>, it is parsed as an octal number

<p>
</li>
<li> 
if the number starts with <code>0b</code>, is is parsed as a binary number

<p>
</li>
<li> 
otherwise, the number is parsed as a decimal number

<p>
</li>
</ul><blockquote>
</blockquote>

<p>
The conversion is done by calling either <code>int()</code> or <code>long()</code> with
the appropriate base (2, 8, 10, or 16).  If this fails, so will <tt class="module">optparse</tt>,
although with a more useful error message.

<p>
<code>float</code> and <code>complex</code> option arguments are converted directly with
<code>float()</code> and <code>complex()</code>, with similar error-handling.

<p>
<code>choice</code> options are a subtype of <code>string</code> options.  The <code>choices</code>
option attribute (a sequence of strings) defines the set of allowed
option arguments.  <code>optparse.check_choice()</code> compares
user-supplied option arguments against this master list and raises
OptionValueError if an invalid string is given.

<p>

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<span class="release-info">Release 2.5.1, documentation updated on 18th April, 2007.</span>
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